okay I am having some issues (i think) withthe expected value and variance of my PDF.
Let me see if I have it right.
My pdf is 2/(x^3) from 1 to 2000.
I get my mean to be 2 and my
variance to be 2 log(2000)-4. Is that correct? If you look at the graph it doesnt seem to be right (the mean is the right solid red bar.) maybe it is because it just extends so far?
My 'by hand' calculation is in agreement with integrate 2/x^3 from 1 to 2000 - Wolfram|Alpha
Approximately 1 is NOT the same as 1. It is NOT a valid pdf. There is no point in doing the question.